An abortion rights activist has pleaded guilty in Manhattan to threatening two anti-abortion advocates in an online posting.

The U.S. District Attorney's Office says 51-year-old Theodore Shulman pleaded guilty in a federal court in Manhattan yesterday to transmitting a threat to injure another person.

Prosecutors say Shulman made the threat in a 2010 posting on the website of a Catholic magazine. The threat targeted the director of New Dorp-based Priests for Life Rev. Frank Pavone and Princeton University professor Robert George, saying someone will kill them if anti-abortion activist Scott Roeder is acquitted. Roeder was subsequently convicted of murdering Wichita abortion provider George Tiller.

Shulman, the son of famed feminist author and activist Alix Kates Shulman, faces up to 5 years in prison and a maximum fine of $250,000 at his Sept. 12 sentencing.